Highly Nanoporous Nickel Cobaltite Hexagonal Nanostructure‐Graphene Composites for the Next Generation Energy Storage/Conversion Devices

Abstract

set forth to study their physicochemical properties of electroactive materials in order to uncover the bottlenecks and further achieve advances in next generation energy devices at low cost. [10] Synergistic effects widen the properties of binary metal oxides for the applications such as in catalyses, electronics, and sensors. Their abundant redox active sites and relatively higher conductivity than that of the monometal oxide can be also efficiently utilized to prepare active electrode materials of energy storage and conversion devices. [11][12][13][14][15][16] Among bimetal oxides, nickel cobaltite has received tremendous attention owning to its low cost, high activity, and good stability. Recently numerous NiCo 2 O 4 micro-and mesostructures such as nanosheets, nanowires, nanoneedles, nanorods, core ring nanoplates, and several hollow mesostructured materials were reported as potential energy device electrodes. [17][18][19][20][21][22][23][24] However, existing materials are still unsatisfactory in terms of energy delivery and activity. It is inevitably required to develop cheap and efficient materials for energy devices. Designing the architecture of an active material is always a great interest especially for energy devices. [25][26][27] It is recognized that favorable structure, easy mass storage, and high conductivity of the active materials can minimize the energy depletion at high current. Thus investigation of active materials tailored with these properties is demanded for modern energy devices.Here we reported a rational design for the controllable construction of spinel type nickel cobaltite-graphene nanostructures as high-performance energy storage/conversion electrodes. Plenty of chemical active sites originated from building blocks and sub-units imported great activity to the electrode materials, while large surface to bulk ratio enhanced the electrode-electrolyte contact. Interestingly, shell ring structures alleviated the volume changes during the continuous cycling process. Further, ample electrolyte storage and fast ion diffusion rate were identified to directly associate with large pore volume and complex pore structures. We used the resultant active electrode materials to fabricate symmetric supercapacitors (SSCs), which exhibited remarkable specific capacitance of 537 F g −1 and retained three fourth of original capacitance at 30 A g −1 . When these electrode materials were assembled as asymmetric supercapacitor (ASC) with the use of graphene-singleThe design and assembly of innovative heterostructures comprising of multifunctional properties are technically important for the applications in efficient energy devices. Here, a novel method is reported to construct hierarchical nanostructures as functional materials for the fabrication of high-performance energy devices. Optimized conditions and extensive spectroscopic studies are performed to understand the morphology evolution. Tunable structure, richer redox active sites, enhanced mass storage, and fast electron transfer cumulatively ensure ...

Preparation of 3D spherical Ni/Al LDHs with significantly enhanced electrochemical performance as a superior cathode material for Ni/MH batteries

“…Zha et al reported that the specific capacity of Co/Ni LDHs is up to 250.69 -339.58 mAh g −1 at a current density of 0.5 A g −1 [17][18][19][20][21][22]. Aluminum (Al) is an element of high abundance in Earth crust and can significantly stabilize the structure of Ni/Al LDHs, so it becomes one of the most attractive elements for substitution .…”

Sulfur‐Induced Interface Engineering of Hybrid NiCo2O4@NiMo2S4 Structure for Overall Water Splitting and Flexible Hybrid Energy Storage

“…[1][2][3][4] Among them, electrocatalytic water splitting 270 and 84 mV, respectively. [1][2][3][4] Among them, electrocatalytic water splitting 270 and 84 mV, respectively.…”

“…To meet the increasing energy source demands and seek for suitable alternative to traditional fossil fuels, many efforts have been made to investigate advanced energy storage and conversion systems. [1][2][3][4] Among them, electrocatalytic water splitting 270 and 84 mV, respectively. [18] Wang's group prepared hybrid NiCo 2 O 4 @NiFe-LDH structures with the overpotential of 290 mV (53 mV dec −1 ) for OER and 192 mV (59 mV dec −1 ) for HER and a cell voltage of 1.6 V at 10 mA cm −2 .…”

Three-dimensional “skin-framework” hybrid network as electroactive material platform for high-performance solid-state asymmetric supercapacitor

“…[1][2][3][4][5][6] Solid-state asymmetric supercapacitors (ASCs), which are a new type of energy storage device, are assembled from positive and negative electrodes of different voltage windows. [7][8][9][10][11][12] They are capable of operation over a wider voltage range, resulting in higher energy and power densities. These remarkable characteristics make them very attractive as ideal energy storage devices for portable electronics.…”